Research into the fundamental underlying processes that govern how ecosystems function is crucial to understanding the natural world.

Species do not exist in isolation, but embedded in a complex community of organisms that interact with each other, and changes in the strengths of these interactions can alter the chemical properties of ecosystems. I recently showed how the removal of predators from an ecosystem can alter the densities of the species they consume, leading to cascading changes in the natural community, and the carbon dioxide emissions of the ecosystem (Atwood, Hammill et al. 2013).

Crucially, more than 50% of the effects of predators on communities and ecosystem function is due to the effects of fear.I have recently shown that the threat of predation alone can be sufficient to alter the structure of ecological communities (Forbes & Hammill 2013), and the ecosystem functions they perform (Hammill et al 2015). This work demonstrated at the community level that the fear of predation alone can have dramatic effects on prey species (Hammill et al. 2008, Hammill et al. 2010).Hammill, E., Atwood, T. B., and Srivastava, D. S. 2015. Predation threat alters composition and functioning of bromeliad ecosystems. Ecosystems 18: 857-866